This invention relates to an improved boom assembly for supporting a tool for conditioning metals and the like within a high temperature furnace.
Many of the newer furnaces now being introduced for use in reclaiming metals from scrap material utilize relatively large melting beds. Typically the scrap material is randomly deposited in the melting bed where it is exposed to very high melting temperatures. As the material begins to melt, it is very important to more evenly distribute the materials in the bed in order to provide for a more efficient operation. Once melted, any slag that might have formed on the surface of the liquid is skimmed off prior to pouring the metal from the furnace. A single rake-like tool, which is herein referred to as a conditioning tool, is usually employed to carry out both the skimming and material handling functions.
As best illustrated in U.S. Pat. Nos. 943,591, 3,800,965 and 3,931,898, extendable boom assemblies for supporting conditioning tools have been used for quite some time in the art. Typically, the boom is telescoped within some type of horizontally aligned support structure and is adapted to be run out from the support to increase the reach of the conditioning equipment. There is, however, no provision made in any of the prior art devices for cooling either the boom or the tool contained therein. As a consequence, the usable life of the equipment in a high temperature environment must be relatively short. It is further believed that without some form of cooling, the unsupported end of a boom of any considerable length will in a short period of time warp or sag when exposed to high furnace temperatures whereupon the boom might become lodged in the furnace and thus difficult to remove without damaging the furnace structure.
Hand-held tools, as typically used to skim slag from small melting furnaces, are sometimes furnished with cooling means to protect both the user and the equipment from becoming overheated. As evidenced in the disclosure in U.S. Pat. Nos. 1,827,504 and 2,198,649, a water jacket is generally formed inside the handle and/or blade of the skimmer and cooling water from a remote source is pumped therethrough to furnish the desired cooling. An extensive amount of hose is needed to supply water to the apparatus, particularly where it is used to service more than one furnace. This hose presents a problem in that it can be severed easily and has a way of becoming fouled in other equipment. Similarly, the use of water as a coolant considerably increases the weight of the equipment and, in the case of an elongated boom or the like, would be prohibitive. Furthermore, the use of water as a coolant is generally limited to low temperature applications. When water is exposed to very high temperatures it can quickly flash to steam, thereby giving rise to all the well-known problems associated with handling this relatively dangerous substance.